diff --git a/tools/anchor_cluster.py b/tools/anchor_cluster.py
index 78ed3ea07dd348975054979000955074d914ccdd..688c37fad0dd1d2c12e1d6b71a0fbf3d94f262a4 100644
--- a/tools/anchor_cluster.py
+++ b/tools/anchor_cluster.py
@@ -20,8 +20,7 @@ import os
 import sys
 # add python path of PadleDetection to sys.path
 parent_path = os.path.abspath(os.path.join(__file__, *(['..'] * 2)))
-if parent_path not in sys.path:
-    sys.path.append(parent_path)
+sys.path.insert(0, parent_path)
 
 from ppdet.utils.logger import setup_logger
 logger = setup_logger('ppdet.anchor_cluster')
diff --git a/tools/eval.py b/tools/eval.py
index bf75555c1149249101cf47f655ce145792047bcc..f78e3a4c099407d5f4403f9b6abff9c3fbcc74da 100755
--- a/tools/eval.py
+++ b/tools/eval.py
@@ -21,8 +21,7 @@ import sys
 
 # add python path of PadleDetection to sys.path
 parent_path = os.path.abspath(os.path.join(__file__, *(['..'] * 2)))
-if parent_path not in sys.path:
-    sys.path.append(parent_path)
+sys.path.insert(0, parent_path)
 
 # ignore warning log
 import warnings
diff --git a/tools/eval_mot.py b/tools/eval_mot.py
index 4e03eaf1b0f6b61e74a460dabf605daf76932e4e..fb8e296124dd9ef5470216e4d00161446b8349be 100644
--- a/tools/eval_mot.py
+++ b/tools/eval_mot.py
@@ -21,8 +21,7 @@ import sys
 
 # add python path of PadleDetection to sys.path
 parent_path = os.path.abspath(os.path.join(__file__, *(['..'] * 2)))
-if parent_path not in sys.path:
-    sys.path.append(parent_path)
+sys.path.insert(0, parent_path)
 
 # ignore warning log
 import warnings
diff --git a/tools/export_model.py b/tools/export_model.py
index ddb7deb177ca4bd16fe1a4a95887813b3858b573..deac2ea128b94668f0d2b743910b09cf09e1f1a0 100644
--- a/tools/export_model.py
+++ b/tools/export_model.py
@@ -21,8 +21,7 @@ import sys
 
 # add python path of PadleDetection to sys.path
 parent_path = os.path.abspath(os.path.join(__file__, *(['..'] * 2)))
-if parent_path not in sys.path:
-    sys.path.append(parent_path)
+sys.path.insert(0, parent_path)
 
 # ignore warning log
 import warnings
diff --git a/tools/infer.py b/tools/infer.py
index b24c205ff23196d2bd884646ca7d1f4474ef2a28..74158d1bb68eeeac74cbac51807c36900ddfcc5f 100755
--- a/tools/infer.py
+++ b/tools/infer.py
@@ -21,8 +21,7 @@ import sys
 
 # add python path of PadleDetection to sys.path
 parent_path = os.path.abspath(os.path.join(__file__, *(['..'] * 2)))
-if parent_path not in sys.path:
-    sys.path.append(parent_path)
+sys.path.insert(0, parent_path)
 
 # ignore warning log
 import warnings
diff --git a/tools/infer_mot.py b/tools/infer_mot.py
index 74b12fd4437044b6f5c254dd8b24e98790c9b39b..1131bcd0751560a54d9fd8a69ea8e5edd4429fe8 100644
--- a/tools/infer_mot.py
+++ b/tools/infer_mot.py
@@ -21,8 +21,7 @@ import sys
 
 # add python path of PadleDetection to sys.path
 parent_path = os.path.abspath(os.path.join(__file__, *(['..'] * 2)))
-if parent_path not in sys.path:
-    sys.path.append(parent_path)
+sys.path.insert(0, parent_path)
 
 # ignore warning log
 import warnings
diff --git a/tools/train.py b/tools/train.py
index a49885cb4f839419b32c0708124005349cf29737..9dff474026b8801f907d11655a13c7c9eba3950c 100755
--- a/tools/train.py
+++ b/tools/train.py
@@ -21,8 +21,7 @@ import sys
 
 # add python path of PadleDetection to sys.path
 parent_path = os.path.abspath(os.path.join(__file__, *(['..'] * 2)))
-if parent_path not in sys.path:
-    sys.path.append(parent_path)
+sys.path.insert(0, parent_path)
 
 # ignore warning log
 import warnings